TI's USB-friendly battery charger with Power-Path for 4.35 V batteries
Texas Instruments' bq2423xH series of devices are highly integrated Li-ion linear chargers and system power-path management devices targeted at space-limited portable applications. The devices operate from either a USB port or AC adapter and support charge currents between 25 mA and 500 mA. The high-input-voltage range with input overvoltage protection supports low-cost, unregulated adapters. The USB input current limit accuracy and start-up sequence allow the bq2423xH to meet USB-IF inrush current specification. Additionally, the input Dynamic Power Management (VIN-DPM) prevents the charger from crashing poorly designed or incorrectly configured USB sources. The bq2423xH features dynamic power-path management (DPPM) that powers the system while simultaneously and independently charging the battery. The DPPM circuit reduces the charge current when the input current limit causes the system output to fall to the DPPM threshold, thus supplying the system load at all times while monitoring the charge current separately. This feature reduces the number of charge and discharge cycles on the battery, allows for proper charge termination, and enables the system to run with a defective or absent battery pack.